ORIGINAL: Luchnia
ORIGINAL: hugger-4641
Flutter is exactly that, a ''flutter'' or oscilation of the aileron during flight that is usually noticed due to the ''rippling' sound it makes. It can also happen to the elevator and rudder. There is some debate as to its true cause, and I believe there can be more than one cause, but it can definitely bring your airplane down. The usual suspect is too large a gap in the hinge area between the aileron and the wing, but the construction of the aileron can also be part of the problem. I've only had aileron flutter occur on one plane so far. It was a Stick .40, and it only occurred comming out of high speed dives. I believe it was due to ailerons on this plane having a very large covering surface stretched over a minimal frame structure. This allowed too much flex in the covering and allowed a ''billowing'' effect in the covering that caused the ''flutter''.
I have heard guys say it is the gap that causes it, but to me I question this because I have seen planes with a huge gap in them and never a flutter at all. I believe it may be a combination of things.
We heard a Sig Cavalier flutter like crazy one time and we all looked because we knew it was going to hit the ground with a thud. The pilot slowed down and then landed and we looked it over and could not find one thing wrong with it. Everything on it was tight and well secure with very little aileron gap. We never heard the flutter return again.
Exactly what happened to this Stick .40, no gap, and nothing else wrong with the aileron, other than large open areas in the frame work. I agree that there is probably not one simple cause. Gap may cause it, but I've never experienced it. In any given case it could be a combination of several things like the aileron construction, balance of lift, and the type of airfoils involved. This Stick .40 had a fully symetrical air foil in the wing, but the ailerons did not have any taper in the chord, just a flat constuction with beveled le and te on the aileron itself. I did not get a chance to experiment with the ailerons as a buddy borrowed and crashed it. But I would have liked to try adding counter weight to the ailerons, and/or building new ailerons with some sheeting over the large open areas.
